package bill.study.enums.suntutorial;

public enum Planet {
	MERCURY(3.303e+23, 2.4397e6), VENUS(4.869e+24, 6.0518e6), EARTH(5.976e+24,
			6.37814e6), MARS(6.421e+23, 3.3972e6), JUPITER(1.9e+27, 7.1492e7), SATURN(
			5.688e+26, 6.0268e7), URANUS(8.686e+25, 2.5559e7), NEPTUNE(
			1.024e+26, 2.4746e7);

	private final double mass; // in kilograms
	private final double radius; // in meters

	Planet(double mass, double radius) {
		this.mass = mass;
		this.radius = radius;
	}

	private double mass() {
		return mass;
	}

	private double radius() {
		return radius;
	}

	// universal gravitational constant (m3 kg-1 s-2)
	public static final double G = 6.67300E-11;

	double surfaceGravity() {
		return G * mass / (radius * radius);
	}

	double surfaceWeight(double otherMass) {
		return otherMass * surfaceGravity();
	}

	public static void main(String[] args) {
//		if (args.length != 1) {
//			System.err.println("Usage:  java Planet <earth_weight>");
//			System.exit(-1);
//		}
		double earthWeight = 100;//Double.parseDouble(args[0]);
		double mass = earthWeight / EARTH.surfaceGravity();
		for (Planet p : Planet.values())
			System.out.printf("Your weight on %s is %f%n", p, p
					.surfaceWeight(mass));
	}
}
